JPWO2018159757A1 - Manufacturing method of reflective layer - Google Patents

Abstract

The present invention provides a method for producing a reflective layer having excellent diffuse reflectivity. The method for producing a reflective layer according to the present invention is a method for producing a reflective layer in which a cholesteric liquid crystal phase is fixed and a bright part and a dark part derived from a cholesteric liquid crystal phase are observed in a section by a scanning electron microscope. Forming a composition layer containing a liquid crystal compound having a polymerizable group and a chiral agent, and undulating bright and dark portions derived from the cholesteric liquid crystal phase observed with a scanning electron microscope in the cross section of the formed composition layer Step 1 for carrying out the treatment to be changed to, and Step 2 for subjecting the composition layer obtained in Step 1 to immobilization treatment. In the immobilization treatment in Step 2, the composition layer is The viscosity of the constituent composition is 2000 mPa · s or more.

Description

  The present invention relates to a method for manufacturing a reflective layer.

  A layer formed by fixing a cholesteric liquid crystal phase is known as a layer having a property of selectively reflecting either right circularly polarized light or left circularly polarized light in a specific wavelength range. Therefore, it is developed for various uses, and is used as, for example, a retardation layer (Patent Document 1). In Patent Document 1, the direction of the alignment regulating force of the alignment film is in a random state, and the direction of the director of the liquid crystal compound in contact with the alignment film is random.

JP 2005-49866 A

On the other hand, in order to apply a layer in which a cholesteric liquid crystal phase is fixed to a projection image display member such as a projection screen, an increase in viewing angle is required.
More specifically, normally, when light is incident from the normal direction of the surface of the layer formed by fixing the cholesteric liquid crystal phase, either right circularly polarized light or left circularly polarized light is selectively reflected. . At this time, if reflection is performed not only in the normal direction but also in an oblique direction, the visibility from the oblique direction is improved. That is, the reflective layer is required to be excellent in characteristics (so-called diffuse reflection) that reflects incident light in various directions.
The present inventors made a reflective layer using the alignment film not subjected to the rubbing treatment described in Patent Document 1, and examined the diffuse reflectance. As a result, the diffuse reflectance satisfied the recent required level. There was no need for further improvement.

  This invention makes it a subject to provide the manufacturing method of the reflection layer which has the outstanding diffuse reflection property in view of the said situation.

The inventors of the present invention have made extensive studies on the above problems and have found that the above problems can be solved by a predetermined procedure.
That is, it has been found that the above problem can be solved by the following configuration.

(1) A method for producing a reflective layer in which a cholesteric liquid crystal phase is fixed and a bright portion and a dark portion derived from a cholesteric liquid crystal phase are observed in a cross section with a scanning electron microscope,
A composition layer containing a liquid crystal compound having a polymerizable group and a chiral agent is formed, and the bright and dark portions derived from the cholesteric liquid crystal phase observed in a scanning electron microscope in the cross section of the formed composition layer are changed into waves Step 1 for performing the process of
Step 2 for performing immobilization treatment on the composition layer obtained in Step 1,
The manufacturing method of a reflective layer whose viscosity of the composition which comprises a composition layer is 2000 mPa * s or more in the case of the fixing process of the process 2.
(2) The method for producing a reflective layer according to (1), wherein the viscosity is 10,000 mPa · s or more.
(3) The manufacturing method of the reflective layer as described in (1) or (2) whose viscosity is 15000 mPa * s or more.
(4) The manufacturing method of the reflective layer in any one of (1)-(3) whose immobilization process is a light irradiation process.
(5) The manufacturing method of the reflective layer in any one of (1)-(4) whose process in the process 1 is a process which changes the helical induction force of the chiral agent contained in a composition layer.
(6) In any one of (1) to (5), the treatment in step 1 is a treatment for cooling or heating the composition layer and changing the helical induction force of the chiral agent contained in the composition layer. The manufacturing method of the reflection layer of description.
(7) The treatment in step 1 heats the composition layer to align the liquid crystal compound to a cholesteric liquid crystal phase, and then the helical induction force of the chiral agent contained in the composition layer increases by 5% or more. The method for producing a reflective layer according to (5) or (6), wherein the composition layer is cooled as described above.
(8) The method for producing a reflective layer according to (7), wherein when the composition layer is cooled, the composition layer is cooled so that the temperature of the composition layer is lowered by 30 ° C. or more.
(9) The manufacturing method of the reflective layer in any one of (1)-(4) whose process in the process 1 is a process which applies a voltage to a composition layer.
(10) The method for producing a reflective layer according to any one of (1) to (9), wherein the liquid crystal compound has a plurality of polymerizable groups.
(11) The manufacturing method of the reflective layer in any one of (1)-(10) whose content of the liquid crystal compound in a composition layer is 60 mass% or more.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the reflection layer which has the outstanding diffuse reflection property can be provided.

It is a schematic diagram at the time of observing the cross section of the layer of a general cholesteric liquid crystal phase state with a scanning electron microscope (SEM: Scanning Electron Microscope). It is a schematic diagram at the time of observing the cross section of the reflective layer manufactured with the manufacturing method of this invention by SEM.

Hereinafter, the present invention will be described in detail. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
In the present specification, “(meth) acrylate” is a notation representing both acrylate and methacrylate, and “(meth) acryloyl group” is a notation representing both an acryloyl group and a methacryloyl group, “(Meth) acryl” is a notation representing both acrylic and methacrylic.

First, FIG. 1 shows a schematic cross-sectional view when a layer of a composition in a general cholesteric liquid crystal phase state is disposed on a substrate. As shown in FIG. 1, when a cross section of a layer 12a of a composition in a cholesteric liquid crystal phase disposed on a substrate 10 is observed with a scanning electron microscope (SEM), stripes of bright portions 14 and dark portions 16 are usually observed. A pattern is observed. That is, in the cross section of the cholesteric liquid crystal phase, a layered structure in which bright portions 14 and dark portions 16 are alternately stacked is observed.
The two bright portions 14 and the three dark portions 16 in FIG. 1 correspond to one pitch of the spiral.
In general, as shown in FIG. 1, the stripe pattern (layered structure) of the bright portion 14 and the dark portion 16 is formed to be parallel to the surface of the substrate 10. In other words, the line forming the bright portion 14 (continuous line) and the line forming the dark portion 16 (continuous line) are parallel to the surface of the composition layer 12a. In such an embodiment, when light is incident from the normal direction of the composition layer 12a in the cholesteric liquid crystal phase state, the light is reflected in the normal direction, but the light is not easily reflected in the oblique direction, It is inferior in diffuse reflectance (see the arrow in FIG. 1).

In FIG. 2, the cross-sectional schematic diagram at the time of arrange | positioning the reflective layer obtained by the manufacturing method of this invention on a board | substrate is shown. As shown in FIG. 2, in the reflective layer 12b, the bright part 14 and the dark part 16 derived from the cholesteric liquid crystal phase have a wave-like structure (undulation structure). That is, the line forming the bright part 14 (continuous line) and the line forming the dark part 16 (continuous line) are wavy. When light is incident on the reflective layer 12b having such a wavy structure (uneven structure) from the normal direction of the reflective layer 12b, a region where the spiral axis of the liquid crystal compound is inclined as shown in FIG. Therefore, part of the incident light is reflected in an oblique direction (see the arrow in FIG. 2). That is, the reflective layer produced by the production method of the present invention is excellent in diffuse reflectance.
In the production method of the present invention for producing the reflective layer as described above, the bright layer and the dark portion derived from the cholesteric liquid crystal phase in the composition layer are changed to be wavy by a predetermined treatment, and the composition layer in that state Is subjected to immobilization treatment to produce a predetermined reflective layer. In particular, when the viscosity of the composition constituting the composition layer is equal to or higher than a predetermined value during the immobilization treatment, the wavy structure is maintained in the bright and dark portions derived from the cholesteric liquid crystal phase obtained in Step 1. It is easy to obtain a reflective layer that is easily fixed and has excellent diffuse reflectivity.

The manufacturing method of the reflective layer of this invention has the following process 1 and 2 at least.
Step 1: A composition layer containing a liquid crystal compound having a polymerizable group and a chiral agent is formed, and bright and dark portions derived from a cholesteric liquid crystal phase observed with a scanning electron microscope in a cross section of the formed composition layer Step 2 for carrying out the treatment to change into wavy Step: Step for immobilizing the composition layer obtained in Step 1 Hereinafter, materials used in each step and the procedure of each step will be described in detail. .

<Step 1>
Step 1 forms a composition layer containing a liquid crystal compound having a polymerizable group and a chiral agent, and a bright portion and a dark portion derived from a cholesteric liquid crystal phase observed with a scanning electron microscope in a cross section of the formed composition layer Is a step of performing a process of changing the waveform into a wave shape.
Below, the material and member used at this process are explained in full detail first, and the procedure of a process is explained in full detail after that.

(Liquid crystal compound)
The kind of liquid crystal compound is not particularly limited.
In general, liquid crystal compounds can be classified into a rod-shaped type (rod-shaped liquid crystal compound) and a disk-shaped type (discotic liquid crystal compound, disk-shaped liquid crystal compound) based on the shape. Furthermore, the rod-shaped type and the disk-shaped type include a low molecular type and a high molecular type, respectively. Polymer generally refers to a polymer having a degree of polymerization of 100 or more (Polymer Physics / Phase Transition Dynamics, Masao Doi, 2 pages, Iwanami Shoten, 1992). In the present invention, any liquid crystal compound can be used. Two or more liquid crystal compounds may be used in combination.

The liquid crystal compound has a polymerizable group. The kind of the polymerizable group is not particularly limited, and a functional group capable of addition polymerization reaction is preferable, and a polymerizable ethylenically unsaturated group or a ring polymerizable group is more preferable. More specifically, the polymerizable group is preferably a (meth) acryloyl group, a vinyl group, a styryl group, an allyl group, an epoxy group, or an oxetane group, and more preferably a (meth) acryloyl group.
The number of polymerizable groups is not particularly limited, and may be one or more. Among them, the number of polymerizable groups is preferably plural, more preferably 2 to 6, and even more preferably 2 to 4 in that the diffuse reflectance of the reflective layer is more excellent. .

The molecular weight of the liquid crystal compound is not particularly limited, but is preferably 400 or more and more preferably 700 or more in that the viscosity of the composition during the immobilization treatment in Step 2 can be easily controlled. The upper limit is not particularly limited, but is often 2000 or less (particularly in the case of a low molecular type).
When a rod-shaped liquid crystal compound is used, from the viewpoint of controlling the viscosity, a compound having 4 or more rings in the core portion of the mesogenic group in the liquid crystal compound is preferable, and a compound having 5 or more rings is more preferable.

  As the liquid crystal compound, a liquid crystal compound represented by the following formula (I) is preferable in that the diffuse reflectance of the reflective layer is more excellent.

Where
A represents a phenylene group which may have a substituent or a trans-1,4-cyclohexylene group which may have a substituent,
L is a single bond, or —CH ₂ O—, —OCH ₂ —, — (CH ₂ ) ₂ OC (═O) —, —C (═O) O (CH ₂ ) ₂ —, —C (= O) O-, -OC (= O)-, -OC (= O) O-, -CH = CH-C (= O) O-, -OC (= O) -CH = CH-, -CH = A linking group selected from the group consisting of N—N═CH—, —C═N—, —N═C—, —C≡C—, and —NH—,
m represents an integer of 3 to 12,
Sp ¹ and Sp ² are each independently ^one or ^two in a single bond or a linear or branched alkylene group having 1 to 20 carbon atoms and a linear or branched alkylene group having 1 to 20 carbon atoms. When two or more —CH ₂ — are —O—, —S—, —NH—, —N (CH ₃ ) —, —C (═O) —, —OC (═O) —, or —C (═O ) Represents a linking group selected from the group consisting of groups substituted with O-
Q ¹ and Q ² each independently represent a hydrogen atom or a polymerizable group selected from the group consisting of groups represented by the following formulas (Q-1) to (Q-5), One of Q ¹ and Q ² represents a polymerizable group;

A is a phenylene group which may have a substituent, or a trans-1,4-cyclohexylene group which may have a substituent. In this specification, the phenylene group is preferably a 1,4-phenylene group.
The m A's may be the same as or different from each other.
In addition, when the trans-1, 4-cyclohexylene group which may have a substituent is contained as A, it has the substituent represented by A at the point which the diffuse reflection property of a reflection layer is more excellent. A liquid crystal compound satisfying mc> 0.1 is preferable, and a liquid crystal satisfying 0.4 ≦ mc ≦ 0.8, where mc is a number obtained by dividing the number of trans-1,4-cyclohexylene groups that may be divided by m. More preferably, it is a compound.
The mc is a number represented by the following calculation formula.
mc = (number of trans-1,4-cyclohexylene groups optionally having a substituent represented by A) / m

  m represents an integer of 3 to 12, preferably an integer of 3 to 9, more preferably an integer of 3 to 7, and still more preferably an integer of 3 to 5.

In the formula (I), the substituent that the phenylene group and trans-1,4-cyclohexylene group may have is not particularly limited, and examples thereof include an alkyl group, a cycloalkyl group, an alkoxy group, and an alkyl ether. And a substituent selected from the group consisting of a group composed of a group, an amide group, an amino group, a halogen atom, and two or more of the above substituents. Further, examples of the substituent include the substituents represented by ^{-C (= O) -X 3 -Sp} 3 -Q 3 below. The phenylene group and trans-1,4-cyclohexylene group may have 1 to 4 substituents. When it has two or more substituents, the two or more substituents may be the same or different from each other.

  In this specification, the alkyl group may be linear or branched. 1-30 are preferable, as for carbon number of an alkyl group, 1-10 are more preferable, and 1-6 are more preferable. Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, Examples include 1,1-dimethylpropyl group, n-hexyl group, isohexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, and dodecyl group. The description of the alkyl group in the alkoxy group is the same as the description regarding the alkyl group. In the present specification, specific examples of the alkylene group referred to as an alkylene group include a divalent group obtained by removing one arbitrary hydrogen atom in each of the above examples of the alkyl group. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

  In the present specification, the cycloalkyl group preferably has 3 or more carbon atoms, more preferably 5 or more, more preferably 20 or less, still more preferably 10 or less, still more preferably 8 or less, and particularly preferably 6 or less. Examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group.

Examples of the substituent that the phenylene group and trans-1,4-cyclohexylene group may have include an alkyl group, an alkoxy group, and a group consisting of —C (═O) —X ³ —Sp ³ —Q ^3. Substituents selected from are preferred. Here, X ³ represents a single bond, —O—, —S—, or —N (Sp ⁴ -Q ⁴ ) —, or represents a nitrogen atom that forms a ring structure with Q ³ and Sp ^3. Show. Sp ³ and Sp ⁴ are each independently one or two in a single bond or a linear or branched alkylene group having 1 to 20 carbon atoms and a linear or branched alkylene group having 1 to 20 carbon atoms. When two or more —CH ₂ — are —O—, —S—, —NH—, —N (CH ₃ ) —, —C (═O) —, —OC (═O) —, or —C (═O ) Represents a linking group selected from the group consisting of groups substituted with O-.
Q ³ and Q ⁴ are each independently a hydrogen atom, a cycloalkyl group, or a cycloalkyl group in which one or more —CH ₂ — is —O—, —S—, —NH—, —N (CH ₃ )-, -C (= O)-, -OC (= O)-, or a group substituted with -C (= O) O-, or a group represented by formula (Q-1) to formula (Q-5) Any polymerizable group selected from the group consisting of:

In the cycloalkyl group, one or more of —CH ₂ — is —O—, —S—, —NH—, —N (CH ₃ ) —, —C (═O) —, —OC (═O). Specific examples of the group substituted with-or -C (= O) O- include a tetrahydrofuranyl group, a pyrrolidinyl group, an imidazolidinyl group, a pyrazolidinyl group, a piperidyl group, a piperazinyl group, and a morpholinyl group. . Of these, a tetrahydrofuranyl group is preferable, and a 2-tetrahydrofuranyl group is more preferable.

In the formula (I), L represents a single bond, —CH ₂ O—, —OCH ₂ —, — (CH ₂ ) ₂ OC (═O) —, —C (═O) O (CH ₂ ) _2. -, -C (= O) O-, -OC (= O)-, -OC (= O) O-, -CH = CH-C (= O) O-, -OC (= O) -CH = A linking group selected from the group consisting of CH—, —CH═N—N═CH—, —C═N—, —N═C—, —C≡C—, and —NH— is shown. L is preferably —C (═O) O—, —OC (═O) —, or —NH—.
The m Ls may be the same as or different from each other.

Sp ¹ and Sp ² are each independently ^one or ^two in a single bond or a linear or branched alkylene group having 1 to 20 carbon atoms and a linear or branched alkylene group having 1 to 20 carbon atoms. Two or more —CH ₂ — is —O—, —S—, —NH—, —N (CH ₃ ) —, —C (═O) —, —OC (═O) —, or —C (= O) A linking group selected from the group consisting of groups substituted with O-. Sp ¹ and Sp ² are each independently a carbon to which a linking group selected from the group consisting of —O—, —OC (═O) —, and —C (═O) O— is bonded to both ends. Selected from the group consisting of a linear alkylene group having 1 to 10 carbon atoms, —OC (═O) —, —C (═O) O—, —O—, and a linear alkylene group having 1 to 10 carbon atoms. It is preferably a linking group composed of one or more groups to be combined, more preferably a straight-chain alkylene group having 1 to 10 carbon atoms having —O— bonded to both ends.

Q ¹ and Q ² each independently represent a hydrogen atom or a polymerizable group selected from the group consisting of groups represented by the following formulas (Q-1) to (Q-5). However, ^one of Q ¹ and Q ² represents a polymerizable group.

  As the polymerizable group, an acryloyl group (formula (Q-1)) or a methacryloyl group (formula (Q-2)) is preferable.

  Specific examples of the liquid crystal compound include a liquid crystal compound represented by the following formula (I-11), a liquid crystal compound represented by the formula (I-21), and a liquid crystal represented by the formula (I-31). Compound etc. are mentioned. In addition to the above, a compound represented by the formula (I) in JP2013-112231A, a compound represented by the formula (I) in JP2010-70543A, a formula of JP2008-291218A Compound represented by (I), compound represented by formula (I) of Japanese Patent No. 4725516, compound represented by general formula (II) of JP2013-087109A, JP2007-176927A The compound described in paragraph 0043 of the above, the compound represented by the formula (1-1) of JP2009-28685A, the compound represented by the general formula (I) of WO2014 / 10325, JP2016-81035A Examples of the compound represented by the formula (1) in the publication and the compounds represented by the formula (2-1) and the formula (2-2) in JP-A No. 2006-121339. It is done.

Liquid crystal compound represented by formula (I-11)

In the formula, R ¹¹ represents a hydrogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms, or —Z ¹² —Sp ¹² —Q ¹² ;
L ¹¹ represents a single bond, —C (═O) O—, or —OC (═O) —,
L ¹² represents —C (═O) O—, —OC (═O) —, —C (═O) NR ² —, or —NR ² C (═O) —,
R ² represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms,
Z ¹¹ and Z ¹² are each independently a single bond, —O—, —NH—, —N (CH ₃ ) —, —S—, —C (═O) O—, —OC (═O) —. , —OC (═O) O—, or —C (═O) NR ¹² —, —NR ¹² C (═O) —,
R ¹² represents a hydrogen atom or —Sp ¹² —Q ¹² ;
Sp ¹¹ and Sp ¹² are each independently a single bond, a linear or branched alkylene group having from carbon atoms 1 be replaced by Q ¹¹ 12 or, carbon atoms, which may be substituted with Q ¹¹ In 1 to 12 linear or branched alkylene groups, any one or more of —CH ₂ — is replaced with —O—, —S—, —NH—, —N (Q ¹¹ ) —, or —C (= O)-represents a linking group obtained by substitution,
Q ¹¹ represents a hydrogen atom, a cycloalkyl group, or a cycloalkyl group in which one or more —CH ₂ — is —O—, —S—, —NH—, —N (CH ₃ ) —, —C (= O)-, -OC (= O)-, or a group substituted with -C (= O) O-, or a group consisting of groups represented by formula (Q-1) to formula (Q-5) A polymerizable group selected from
Q ¹² represents a hydrogen atom or a polymerizable group selected from the group consisting of groups represented by formula (Q-1) to formula (Q-5);
l ¹¹ represents an integer of 0 to 2,
m ¹¹ represents an integer of 1 or 2,
n ¹¹ represents an integer of 1 to 3,
The plurality of R ¹¹ , the plurality of L ¹¹ , the plurality of L ¹² , the plurality of l ¹¹ , the plurality of Z ¹¹ , the plurality of Sp ¹¹ , and the plurality of Q ¹¹ may be the same as or different from each other.
In the liquid crystal compound represented by the formula (I-11), as R ¹¹ , Q ¹² is selected from the group consisting of groups represented by the formula (Q-1) to the formula (Q-5). It contains at least one group —Z ¹² —Sp ¹² —Q ¹² .
In the liquid crystal compound represented by the formula (I-11), Z ¹¹ is —C (═O) O—, —OC (═O) —, —C (═O) NR ¹² —, or —NR ¹² C. (= O) -, ^{and, -Z 11 -Sp 11 -Q 11 Q} 11 is a polymerizable group selected from the group consisting of groups represented by the formula (Q-1) ~ formula (Q-5) Is preferred. In the liquid crystal compound represented by the formula (I-11), as R ¹¹ , Z ¹² is —C (═O) O—, —OC (═O) —, —C (═O) NR ¹² — or ^{-NR 12 C (= O) -} , and, -Z ¹² -Sp Q ¹² is a polymerizable group selected from the group consisting of groups represented by the formula (Q-1) ~ formula (Q-5) preferably a ¹² -Q ^12.

Any 1,4-cyclohexylene group contained in the liquid crystal compound represented by the formula (I-11) is a trans-1,4-cyclohexylene group.
As a preferable embodiment of the liquid crystal compound represented by Formula (I-11), L ¹¹ is a single bond, l ¹¹ is 1 (dicyclohexyl group), and Q ¹¹ is Formula (Q-1) to Formula (Q-5). And a compound that is a polymerizable group selected from the group consisting of groups represented by:
As another preferable embodiment of the liquid crystal compound represented by the formula (I-11), m ¹¹ is 2, l ¹¹ is 0, and two R ¹¹ are both —Z ¹² —Sp ¹² —Q ¹² . , Q ¹² is a polymerizable group selected from the group consisting of groups represented by formula (Q-1) to formula (Q-5).

Liquid crystal compound represented by formula (I-21)

In the formula, Z ²¹ and Z ²² each independently represent a trans-1,4-cyclohexylene group which may have a substituent, or a phenylene group which may have a substituent,
Each of the above substituents is independently 1 to 4 substituents selected from the group consisting of —CO—X ²¹ —Sp ²³ —Q ²³ , an alkyl group, and an alkoxy group,
m21 represents an integer of 1 or 2, n21 represents an integer of 0 or 1,
When m21 represents 2, n21 represents 0,
when m21 represents 2, two Z ²¹ may be the same or different;
At least one of Z ²¹ and Z ²² is an optionally substituted phenylene group,
L ²¹ , L ²² , L ²³ and L ²⁴ are each independently a single bond, or —CH ₂ O—, —OCH ₂ —, — (CH ₂ ) ₂ OC (═O) —, —C (═O ) O (CH ₂ ) ₂ —, —C (═O) O—, —OC (═O) —, —OC (═O) O—, —CH═CH—C (═O) O—, and — A linking group selected from the group consisting of OC (= O) -CH = CH-;
X ²¹ represents —O—, —S—, or —N (Sp ²⁵ —Q ²⁵ ) —, or represents a nitrogen atom that forms a ring structure with Q ²³ and Sp ²³ ,
r ²¹ represents an integer of 1 to 4,
Sp ²¹ , Sp ²² , Sp ²³ , and Sp ²⁵ are each independently a single bond or a linear or branched alkylene group having 1 to 20 carbon atoms and a linear or branched alkylene group having 1 to 20 carbon atoms. In the group, one or more —CH ₂ — is —O—, —S—, —NH—, —N (CH ₃ ) —, —C (═O) —, —OC (═O) —, Or a linking group selected from the group consisting of groups substituted with -C (= O) O-,
Q ²¹ and Q ²² each independently represent any polymerizable group selected from the group consisting of groups represented by formula (Q-1) to formula (Q-5);
Q ²³ represents a hydrogen atom, a cycloalkyl group, or a cycloalkyl group, wherein one or more of —CH ₂ — is —O—, —S—, —NH—, —N (CH ₃ ) —, —C (= O)-, -OC (= O)-, or a group substituted with -C (= O) O-, selected from the group consisting of groups represented by formula (Q-1) to formula (Q-5) Any single polymerizable group, or a single bond in the case where X ²¹ is a nitrogen atom that forms a ring structure with Q ²³ and Sp ²³ ,
Q ²⁵ is a hydrogen atom, a cycloalkyl group, or a cycloalkyl group, wherein one or more of —CH ₂ — is —O—, —S—, —NH—, —N (CH ₃ ) —, —C ( = O)-, -OC (= O)-, or a group substituted with -C (= O) O-, or a group represented by formula (Q-1) to formula (Q-5). When any one of the polymerizable groups selected from the group is selected and Sp ²⁵ is a single bond, Q ²⁵ is not a hydrogen atom.

The liquid crystal compound represented by the formula (I-21) preferably has a structure in which 1,4-phenylene groups and trans-1,4-cyclohexylene groups are alternately present, for example, m21 is 2. n21 is 0, and Z ²¹ is a trans-1,4-cyclohexylene group which may have a substituent from the Q ²¹ side, an arylene group which may have a substituent, Alternatively, m21 is 1, n21 is 1, Z ²¹ is an arylene group which may have a substituent, and Z ²² is an arylene group which may have a substituent. Is preferred.

A liquid crystal compound represented by formula (I-31);

In the formula, R ³¹ and R ³² are each independently a group selected from the group consisting of an alkyl group, an alkoxy group, and —C (═O) —X ³¹ —Sp ³³ —Q ³³ ;
n31 and n32 each independently represents an integer of 0 to 4,
X ³¹ represents a single bond, —O—, —S—, or —N (Sp ³⁴ —Q ³⁴ ) —, or represents a nitrogen atom that forms a ring structure with Q ³³ and Sp ³³ ,
Z ³¹ represents a phenylene group which may have a substituent,
Z ³² represents a trans-1,4-cyclohexylene group which may have a substituent, or a phenylene group which may have a substituent,
Each of the above substituents is independently an alkyl group, an alkoxy group, and 1 to 4 substituents selected from the group consisting of —C (═O) —X ³¹ —Sp ³³ —Q ³³ ,
m31 represents an integer of 1 or 2, m32 represents an integer of 0 to 2,
when m31 and m32 are 2, two Z ³¹ and Z ³² may be the same or different;
L ³¹ and L ³² are each independently a single bond, or —CH ₂ O—, —OCH ₂ —, — (CH ₂ ) ₂ OC (═O) —, —C (═O) O (CH ₂ ). _2- , -C (= O) O-, -OC (= O)-, -OC (= O) O-, -CH = CH-C (= O) O-, and -OC (= O)- Represents a linking group selected from the group consisting of CH = CH-;
Sp ³¹ , Sp ³² , Sp ³³ and Sp ³⁴ are each independently a single bond or a linear or branched alkylene group having 1 to 20 carbon atoms and a linear or branched alkylene group having 1 to 20 carbon atoms. In the group, one or more —CH ₂ — is —O—, —S—, —NH—, —N (CH ₃ ) —, —C (═O) —, —OC (═O) —, Or a linking group selected from the group consisting of groups substituted with -C (= O) O-,
Q ³¹ and Q ³² each independently represent any polymerizable group selected from the group consisting of groups represented by formula (Q-1) to formula (Q-5);
Q ³³ and Q ³⁴ are each independently a hydrogen atom, a cycloalkyl group, or a cycloalkyl group in which one or more —CH ₂ — is —O—, —S—, —NH—, —N (CH ₃ )-, -C (= O)-, -OC (= O)-, or a group substituted with -C (= O) O-, or in formula (Q-1) to formula (Q-5) in the case represented indicates one polymerizable group selected from the group consisting of group, Q ³³ is forming a ring structure with X ³¹ and Sp ^33, may be a single bond, is Sp ³⁴ When it is a single bond, Q ³⁴ is not a hydrogen atom.
As the liquid crystal compound represented by the formula (I-31), particularly preferable compounds include a compound in which Z ³² is a phenylene group and a compound in which m 32 is 0.

The compound represented by the formula (I) preferably has a partial structure represented by the following formula (II).
In formula (II), the black circles indicate the position of bonding with other parts of formula (I). The partial structure represented by the formula (II) may be included as a part of the partial structure represented by the following formula (III) in the formula (I).

In the formula, R ¹ and R ² are each independently selected from the group consisting of a hydrogen atom, an alkyl group, an alkoxy group, and a group represented by —C (═O) —X ³ —Sp ³ —Q ^3. It is a group. Here, X ³ represents a single bond, —O—, —S—, or —N (Sp ⁴ -Q ⁴ ) —, or represents a nitrogen atom that forms a ring structure with Q ³ and Sp ^3. Show. X ³ is preferably a single bond or —O—. R ¹ and R ² are preferably —C (═O) —X ³ —Sp ³ —Q ³ . R ¹ and R ² are preferably the same as each other. The bonding position of R ¹ and R ² to each phenylene group is not particularly limited.

Sp ³ and Sp ⁴ are each independently one or two in a single bond or a linear or branched alkylene group having 1 to 20 carbon atoms and a linear or branched alkylene group having 1 to 20 carbon atoms. The above —CH ₂ — is —O—, —S—, —NH—, —N (CH ₃ ) —, —C (═O) —, —OC (═O) —, or —C (═O). A linking group selected from the group consisting of groups substituted with O- is shown. Sp ³ and Sp ⁴ are each independently preferably a linear or branched alkylene group having 1 to 10 carbon atoms, more preferably a linear alkylene group having 1 to 5 carbon atoms, and a straight chain having 1 to 3 carbon atoms. Even more preferred are chain alkylene groups.
Q ³ and Q ⁴ are each independently a hydrogen atom, a cycloalkyl group, or a cycloalkyl group in which one or more —CH ₂ — is —O—, —S—, —NH—, —N (CH ₃ )-, -C (= O)-, -OC (= O)-or -C (= O) O-, or a group represented by formula (Q-1) to formula (Q-5) Any polymerizable group selected from the group consisting of:

  It is also preferable that the compound represented by the formula (I) has a structure represented by the following formula (II-2), for example.

In the formula, A ¹ and A ² each independently represent a phenylene group which may have a substituent or a trans-1,4-cyclohexylene group which may have a substituent. Each independently is an alkyl group, an alkoxy group, and 1 to 4 substituents selected from the group consisting of —C (═O) —X ³ —Sp ³ —Q ³ ;
L ¹ , L ² and L ³ are each independently a single bond, or —CH ₂ O—, —OCH ₂ —, — (CH ₂ ) ₂ OC (═O) —, —C (═O) O ( CH ₂ ) ₂ —, —C (═O) O—, —OC (═O) —, —OC (═O) O—, —CH═CH—C (═O) O—, and —OC ( ═O) represents a linking group selected from the group consisting of —CH═CH—,
n1 and n2 each independently represent an integer of 0 to 9, and n1 + n2 is 9 or less.
^{Q 1, Q 2, Sp 1} , and the definition of Sp ² are the same as those defined for each group in the above formula (I). The definitions of X ³ , Sp ³ , Q ³ , R ¹ , and R ² are the same as the definitions of each group in the above formula (II).

  Examples of the liquid crystal compound represented by the formula (I) and satisfying 0.4 ≦ mc ≦ 0.8 include the following.

Two or more liquid crystal compounds may be used in combination. For example, two or more liquid crystal compounds represented by the formula (I) may be used in combination.
Among them, the liquid crystal compound represented by the above formula (I), which is a liquid crystal compound represented by the formula (I) together with the liquid crystal compound satisfying 0.4 ≦ mc ≦ 0.8, It is preferable to use a liquid crystal compound satisfying <mc <0.3.

Examples of the liquid crystal compound represented by the formula (I) and satisfying 0.1 <mc <0.3 are as follows.

  Another preferred embodiment of the liquid crystal compound includes a compound represented by the following formula (IV).

Compound represented by formula (IV)

Wherein (IV), A ¹ represents an alkylene group having 2 to 18 carbon atoms, two or more CH ₂ not one CH ₂ or adjacent in the alkylene group, substituted by -O- May be;
Z ¹ represents —C (═O) —, —O—C (═O) —, or a single bond;
Z ² represents —C (═O) — or —C (═O) —CH═CH—;
R ¹ represents a hydrogen atom or a methyl group;
R ² is a hydrogen atom, a halogen atom, a linear alkyl group having 1 to 4 carbon atoms, a methoxy group, an ethoxy group, an optionally substituted phenyl group, a vinyl group, a formyl group, a nitro group, or a cyano group. , Acetyl group, acetoxy group, N-acetylamide group, acryloylamino group, N, N-dimethylamino group, maleimide group, methacryloylamino group, allyloxy group, allyloxycarbamoyl group, alkyl group having 1 to 4 carbon atoms An N-alkyloxycarbamoyl group, an N- (2-methacryloyloxyethyl) carbamoyloxy group, an N- (2-acryloyloxyethyl) carbamoyloxy group, or a group represented by the following formula (IV-2) ;
L ¹ , L ² , L ³ and L ⁴ are each independently an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkoxycarbonyl group having 2 to 5 carbon atoms, or 2 to 2 carbon atoms. 4 represents an acyl group, a halogen atom or a hydrogen atom, and at least one of L ¹ , L ² , L ³ and L ⁴ represents a group other than a hydrogen atom.
-Z ⁵ -T-Sp-P type (IV-2)
In formula (IV-2), P represents an acryl group, a methacryl group or a hydrogen atom, Z ⁵ is a single bond, —C (═O) O—, —OC (═O) —, —C (═O). NR ¹ — (R ¹ represents a hydrogen atom or a methyl group), —NR ¹ C (═O) —, —C (═O) S—, or —SC (═O) —, where T is 1 , 4-phenylene, Sp represents a divalent aliphatic group having 1 to 12 carbon atoms which may have a substituent, one CH ₂ in the aliphatic group or _two or more not adjacent to each other CH ₂ of may be substituted with —O—, —S—, —OC (═O) —, —C (═O) O— or —OC (═O) O—.

  The compound represented by the formula (IV) is preferably a compound represented by the following formula (V).

  Compound represented by formula (V)

In the formula (V), n1 represents an integer of 3 to 6;
R ¹¹ represents a hydrogen atom or a methyl group;
Z ¹² represents —C (═O) — or —C (═O) —CH═CH—;
R ¹² is represented by a hydrogen atom, a linear alkyl group having 1 to 4 carbon atoms, a methoxy group, an ethoxy group, a phenyl group, an acryloylamino group, a methacryloylamino group, an allyloxy group, or the following formula (IV-3). Represents a group.
-Z ⁵¹ -T-Sp-P type (IV-3)
In formula (IV-3), P represents an acryl group or a methacryl group;
Z ⁵¹ represents —C (═O) O— or —OC (═O) —;
T represents 1,4-phenylene;
Sp represents a divalent aliphatic group having 2 to 6 carbon atoms which may have a substituent group, one CH ₂ or non-adjacent two or more CH ₂ in the aliphatic groups, -O -, -OC (= O)-, -C (= O) O- or -O (= O) OO- may be substituted.
N1 represents an integer of 3 to 6, and is preferably 3 or 4.
Z ¹² represents —C (═O) — or —C (═O) —CH═CH—, and preferably represents —C (═O) —.
R ¹² is represented by a hydrogen atom, a linear alkyl group having 1 to 4 carbon atoms, a methoxy group, an ethoxy group, a phenyl group, an acryloylamino group, a methacryloylamino group, an allyloxy group, or the above formula (IV-3). And more preferably a methyl group, an ethyl group, a propyl group, a methoxy group, an ethoxy group, a phenyl group, an acryloylamino group, a methacryloylamino group, or a group represented by the above formula (IV-3). More preferably, it represents a methyl group, an ethyl group, a methoxy group, an ethoxy group, a phenyl group, an acryloylamino group, a methacryloylamino group, or a group represented by the above formula (IV-3).

The above R intends Me.
Specific examples of the compound represented by formula (IV) include the compounds exemplified below.

  Another preferred embodiment of the liquid crystal compound includes a compound represented by the following formula (VI).

Compound represented by formula (VI)

In formula (VI), Z ³ represents —C (═O) — or —CH═CH—C (═O) —;
Z ⁴ represents —C (═O) — or —C (═O) —CH═CH—;
R ³ and R ⁴ each independently represent a hydrogen atom, a halogen atom, a linear alkyl group having 1 to 4 carbon atoms, a methoxy group, an ethoxy group, an optionally substituted aromatic ring group, or a cyclohexyl group. , Vinyl group, formyl group, nitro group, cyano group, acetyl group, acetoxy group, acryloylamino group, N, N-dimethylamino group, maleimide group, methacryloylamino group, allyloxy group, allyloxycarbamoyl group, alkyl group carbon N-alkyloxycarbamoyl group having a number of 1 to 4, N- (2-methacryloyloxyethyl) carbamoyloxy group, N- (2-acryloyloxyethyl) carbamoyloxy group or the following formula (VI-2) Represents a group;
L ⁵ , L ⁶ , L ⁷ and L ⁸ are each independently an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkoxycarbonyl group having 2 to 5 carbon atoms, or 2 to 2 carbon atoms. 4 represents an acyl group, a halogen atom or a hydrogen atom, and at least one of L ⁵ , L ⁶ , L ⁷ and L ⁸ represents a group other than a hydrogen atom.
-Z ⁵ -T-Sp-P Formula (VI-2)
In formula (VI-2), P represents an acryl group, a methacryl group or a hydrogen atom, and Z ⁵ represents —C (═O) O—, —OC (═O) —, —C (═O) NR ¹ —. (R ¹ represents a hydrogen atom or a methyl group), —NR ¹ C (═O) —, —C (═O) S—, or —SC (═O) —, and T represents 1,4-phenylene. Sp represents a divalent aliphatic group having 1 to 12 carbon atoms which may have a substituent, and one CH ₂ or _two or more CH ₂ not adjacent to each other in the aliphatic group is , —O—, —S—, —OC (═O) —, —C (═O) O— or —OC (═O) O— may be substituted.

  The compound represented by the formula (VI) is preferably a compound represented by the following formula (VII).

  Compound represented by formula (VII)

Wherein (VII), Z ¹³ is, -C (= O) - or -C (= O) represents -CH = CH-;
Z ¹⁴ represents —C (═O) — or —CH═CH—C (═O) —;
R ¹³ and R ¹⁴ are each independently a hydrogen atom, a linear alkyl group having 1 to 4 carbon atoms, a methoxy group, an ethoxy group, a phenyl group, an acryloylamino group, a methacryloylamino group, an allyloxy group, or the above formula ( Represents a group represented by IV-3).
Z ¹³ represents —C (═O) — or —C (═O) —CH═CH—, and preferably represents —C (═O) —.
R ¹³ and R ¹⁴ are each independently a hydrogen atom, a linear alkyl group having 1 to 4 carbon atoms, a methoxy group, an ethoxy group, a phenyl group, an acryloylamino group, a methacryloylamino group, an allyloxy group, or the above formula (IV -3) represents a group represented by methyl group, ethyl group, propyl group, methoxy group, ethoxy group, phenyl group, acryloylamino group, methacryloylamino group, or group represented by the above formula (IV-3) In particular, it is preferable to represent a methyl group, an ethyl group, a methoxy group, an ethoxy group, a phenyl group, an acryloylamino group, a methacryloylamino group, or a group represented by the above formula (IV-3).

  Specific examples of the compound represented by the formula (VI) include compounds exemplified below.

  Another preferred embodiment of the liquid crystal compound is a compound represented by the following formula (VIII).

  Compound represented by formula (VIII)

Wherein (VIII), A ² and A ³ each independently represent an alkylene group having 2 to 18 carbon atoms, two or more CH ₂ not one CH ₂ or adjacent in the alkylene group , -O- may be substituted;
Z ⁵ represents —C (═O) —, —OC (═O) — or a single bond;
Z ⁶ represents —C (═O) —, —C (═O) O— or a single bond;
R ⁵ and R ⁶ each independently represents a hydrogen atom or a methyl group;
L ⁹ , L ¹⁰ , L ¹¹ and L ¹² are each independently an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkoxycarbonyl group having 2 to 5 carbon atoms, or 2 to 2 carbon atoms. 4 represents an acyl group, a halogen atom or a hydrogen atom, and at least one of L ⁹ , L ¹⁰ , L ¹¹ and L ¹² represents a group other than a hydrogen atom.

  The compound represented by the formula (VIII) is preferably a compound represented by the following formula (IX).

  Compound represented by formula (IX)

In formula (IX), n2 and n3 each independently represent an integer of 3 to 6;
R ¹⁵ and R ¹⁶ each independently represents a hydrogen atom or a methyl group.

In formula (IX), n2 and n3 each independently represent an integer of 3 to 6, and n2 and n3 are preferably 4.
In formula (IX), R ¹⁵ and R ¹⁶ each independently represent a hydrogen atom or a methyl group, and it is preferable that R ¹⁵ and R ¹⁶ represent a hydrogen atom.

  Specific examples of the compound represented by formula (VIII) include the compounds exemplified below.

  The liquid crystal compound can be produced by a known method.

  In the composition layer, the content of the liquid crystal compound is not particularly limited, but is preferably 50% by mass or more, more preferably 60% by mass or more, and further preferably 60 to 95% by mass with respect to the total mass of the composition layer. Especially, it is preferable that content of the liquid crystal compound which has a several polymeric group is the said range at the point which the diffuse reflection property of a reflection layer is more excellent.

(Chiral agent (chiral compound))
The kind of chiral agent is not particularly limited. The chiral agent may be liquid crystalline or non-liquid crystalline. The chiral agent includes various known chiral agents (for example, liquid crystal device handbook, Chapter 3-4, chiral agent for TN (Twisted Nematic), STN (Super Twisted Nematic), 199 pages, Japan Society for the Promotion of Science, 142nd. From the committee edition, described in 1989). Chiral agents generally contain asymmetric carbon atoms. However, an axially asymmetric compound or a planar asymmetric compound that does not contain an asymmetric carbon atom can also be used as a chiral agent. Examples of the axial asymmetric compound or the planar asymmetric compound include binaphthyl, helicene, paracyclophane, and derivatives thereof. The chiral agent may have a polymerizable group.

In the composition, the content of the chiral agent is preferably 0.5 to 30% by mass with respect to the total mass of the liquid crystal compound. A smaller amount of chiral agent is preferred because it tends not to affect liquid crystallinity. Therefore, as the chiral agent, a compound having a strong twisting power is preferable so that a twisted orientation with a desired helical pitch can be achieved even with a small amount.
Examples of the chiral agent exhibiting such a strong twisting force include, for example, JP 2002-302487, JP 2002-80478, JP 2002-80851, JP 2002-179668, and JP 2002. -179670, JP-A 2002-338575, JP-A 2002-180051, JP-A 62-81354, WO 2002/006195, JP-A 2011-241215, JP-A 2003-287623 And chiral agents described in JP-A-2014-034581, and LC-756 manufactured by BASF.

(Optional ingredients)
The composition layer may contain components other than the liquid crystal compound and the chiral agent.

(Polymerization initiator)
The composition layer may contain a polymerization initiator.
The polymerization initiator is preferably a photopolymerization initiator capable of initiating a polymerization reaction by ultraviolet irradiation. Examples of the photopolymerization initiator include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), acyloin ether (described in US Pat. No. 2,448,828), α-hydrocarbon substituted aromatic acyloin. Compound (described in US Pat. No. 2,722,512), polynuclear quinone compound (described in US Pat. Nos. 3,046,127 and 2,951,758), a combination of triarylimidazole dimer and p-aminophenyl ketone (US Pat. No. 3,549,367) No. specification), acridine and phenazine compounds (JP-A-60-105667, US Pat. No. 4,239,850) and oxadiazole compounds (US Pat. No. 4,212,970).
Although content in particular of the polymerization initiator in a composition layer is not restrict | limited, 0.1-20 mass% is preferable with respect to the total mass of a liquid crystal compound, and 1-10 mass% is more preferable.

(Orientation control agent)
The composition layer may contain an orientation control agent. By including an alignment control agent in the composition layer, it becomes possible to form a stable or rapid cholesteric liquid crystal phase.
Examples of the orientation control agent include fluorine-containing (meth) acrylate polymers, compounds represented by the general formulas (X1) to (X3) described in WO2011 / 162291, and paragraphs [0007] of JP2012-211306. ] To [0029], compounds described in paragraphs [0020] to [0031] of JP2013-47204, compounds described in paragraphs [0165] to [0170] of WO2016 / 009648, WO2016 / 092844, paragraphs [0077] to [0081], and general formulas (Cy201) to (Cy211) described in Japanese Patent No. 4592225. These compounds can reduce the tilt angle of the molecules of the liquid crystal compound or substantially horizontally align them at the air interface of the layer. In the present specification, “horizontal alignment” means that the major axis of the liquid crystal molecule is parallel to the film surface, but it is not required to be strictly parallel. An orientation having an inclination angle of less than 20 ° is meant.
An orientation control agent may be used individually by 1 type, and may use 2 or more types together.
Although content in particular of the orientation control agent in a composition layer is not restrict | limited, 0.01-10 mass% is preferable with respect to liquid crystal compound total mass, and 0.01-5 mass% is more preferable.

(Other additives)
The composition layer is composed of one or more kinds of antioxidants, ultraviolet absorbers, sensitizers, stabilizers, plasticizers, chain transfer agents, polymerization inhibitors, antifoaming agents, leveling agents, thickening agents. Other additives such as agents, flame retardants, surfactants, dispersants, and colorants such as dyes and pigments may be included.

In order to increase the viscosity of the composition layer, the composition layer may contain a thickener.
As the thickener, those capable of increasing the viscosity without greatly disturbing the alignment of the liquid crystal are preferable, and for example, a polymer having a mesogenic structure is preferable.
For example, a compound having a hydrogen bonding functional group is also preferable. As the hydrogen bonding functional group, a hydroxyl group, an amino group, a carboxyl group, a sulfo group, an amide group, a urethane group, a urea group, or the like is preferable.

(Procedure of step 1)
In step 1, first, the above-described composition layer is prepared.
The method for producing the composition layer is not particularly limited, and examples thereof include a method for forming a composition layer by applying a composition containing a liquid crystal compound and a chiral agent on a substrate.

The substrate is a plate that supports the composition layer. Among these, a transparent substrate is preferable. The transparent substrate intends a substrate having a visible light transmittance of 60% or more, and the transmittance is preferably 80% or more, and more preferably 90% or more.
The material constituting the substrate is not particularly limited. For example, cellulose polymer, polycarbonate polymer, polyester polymer, (meth) acrylic polymer, styrene polymer, polyolefin polymer, vinyl chloride polymer, amide polymer, imide Examples thereof include a polymer, a sulfone polymer, a polyether sulfone polymer, and a polyether ether ketone polymer.
The substrate may contain various additives such as UV (ultraviolet) absorbers, matting agent fine particles, plasticizers, deterioration inhibitors, and release agents.
The substrate is preferably low birefringence in the visible light region. For example, the retardation of the substrate at a wavelength of 550 nm is preferably 50 nm or less, and more preferably 20 nm or less.
Although the thickness in particular of a board | substrate is not restrict | limited, 10-200 micrometers is preferable from the point of thickness reduction and a handleability, and 20-100 micrometers is more preferable.
The above thickness is intended to be an average thickness, and is obtained by measuring the thickness of any five points of the substrate and arithmetically averaging them.

Moreover, when apply | coating the said composition, the composition may contain the solvent as needed.
Examples of the solvent include water or an organic solvent. Examples of the organic solvent include amides such as N, N-dimethylformamide; sulfoxides such as dimethyl sulfoxide; heterocyclic compounds such as pyridine; hydrocarbons such as benzene and hexane; alkyls such as chloroform and dichloromethane. Halides; esters such as methyl acetate, butyl acetate, and propylene glycol monoethyl ether acetate; ketones such as acetone, methyl ethyl ketone, cyclohexanone, and cyclopentanone; tetrahydrofuran, 1,2-dimethoxyethane, and the like Ethers; 1,4-butanediol diacetate; and the like. These may be used alone or in combination of two or more.

The method for applying the composition onto the substrate is not particularly limited, and examples thereof include a wire bar coating method, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, and a die coating method.
In addition, you may implement the process which dries the composition apply | coated on the board | substrate after application | coating as needed. By carrying out the drying treatment, the solvent can be removed from the applied composition.

  The thickness of the composition layer disposed on the substrate is not particularly limited, but is preferably 0.1 to 20 μm, more preferably 0.2 to 15 μm, more preferably 0.5 to 15 μm, in that the diffuse reflection property of the reflective layer is more excellent. 10 μm is more preferable.

Next, the bright part and the dark part derived from the cholesteric liquid crystal phase observed with a scanning electron microscope in the cross section of the formed composition layer are changed into waves.
More specifically, normally, in the cross section of the composition layer formed by the above procedure, the bright part and dark part derived from the cholesteric liquid crystal phase are parallel to the surface of the composition layer (in other words, the surface of the substrate). (See FIG. 1). That is, the line forming the bright part (continuous line) and the line forming the dark part (continuous line) are both linear so as to be parallel to the surface of the composition layer. By subjecting such a composition layer to a predetermined treatment, the bright part and the dark part derived from the cholesteric liquid crystal phase are changed to be wavy (see FIG. 2). That is, by applying a predetermined treatment, a bright part (line forming a bright part) and a dark part (line forming a dark part) derived from a cholesteric liquid crystal phase observed with a scanning electron microscope in a cross section of the composition layer are respectively straight lines. Change from shape to wave.

  The process for changing the bright part and the dark part derived from the cholesteric liquid crystal phase to be wavy is not particularly limited, and is preferably a process for changing the helical induction force of the chiral agent contained in the composition layer. For example, when the helical induction force of the chiral agent contained in the composition layer increases, the twist of the liquid crystal compound increases in the composition layer, and as a result, the orientation of the cholesteric liquid crystal phase (inclination of the helical axis) changes. As a result, the linear bright part and dark part are changed to the bright part and dark part of the wavy structure (uneven structure), and a predetermined reflective layer (a layer of the composition in the cholesteric liquid crystal phase state) is formed (FIG. 2). reference).

In addition, the helical induction force (HTP) of a chiral agent is a factor which shows the helical orientation capability represented by following formula (1).
Formula (1) HTP = 1 / (length of helical pitch (unit: μm) × concentration of chiral agent)
The length of the helical pitch means the length of the pitch P (= the period of the spiral) of the helical structure of the cholesteric liquid crystal phase in the composition layer, and is measured by the method described on page 196 of the liquid crystal manual (published by Maruzen Co., Ltd.). it can. The concentration of the chiral agent is intended to be the concentration (% by mass) of the chiral agent relative to the total solid content in the composition layer.
The HTP value is affected not only by the type of chiral agent but also by the type of liquid crystal compound contained in the composition layer. Thus, for example, a composition containing a predetermined chiral agent X and a predetermined liquid crystal compound A and a composition containing a predetermined liquid crystal compound B different from the predetermined chiral agent X and the predetermined liquid crystal compound A are prepared and the same. When both HTPs are measured at temperature, the values may be different. The value of HTP varies depending on the length of the helical pitch formed in the composition layer, and the length of the helical pitch can be adjusted as appropriate depending on the temperature of the composition layer. That is, the length of the helical pitch can be adjusted by subjecting the composition layer to cooling treatment or heat treatment.

Especially, it is preferable to implement a treatment that increases the helical induction force of the chiral agent in the composition layer by 5% or more.
When the helical induction force of the chiral agent is increased by 5% or more, the helical induction force of the chiral agent in the composition before the predetermined treatment (for example, cooling treatment) is applied to the composition layer is X, and the predetermined force is applied to the composition layer. When the helical induction force of the chiral agent in the composition layer after the treatment (for example, cooling treatment) is Y, the rate of increase Z represented by the following formula (2) is 5% or more. Intended.
Formula (2): Rate of increase Z (%) = {(Y−X) / X} × 100
The increase rate Z is preferably 5% or more, and more preferably 10% or more. 12% or more is still more preferable at the point which the diffuse reflection property of a reflection layer is more excellent. The upper limit is not particularly limited, but is often 40% or less.

As the treatment for changing the bright part and the dark part derived from the cholesteric liquid crystal phase to be wavy, it is preferable to cool or heat the composition layer to change the helical induction force of the chiral agent contained in the composition layer. .
In particular, as a preferred embodiment, the composition layer is heated to align the liquid crystal compound into a cholesteric liquid crystal phase, and then the helical induction force of the chiral agent contained in the composition layer is changed (preferably, The process which cools a composition layer is mentioned so that it may raise 10% or more.
Hereafter, the said preferable aspect is explained in full detail.

The heating condition for heating the composition layer is 40 to 100 ° C. (preferably 60 to 100 ° C.) for 0.5 to 5 minutes (preferably 0.5 to 2 minutes). It is preferable to heat.
Moreover, when cooling the composition layer in the cholesteric liquid crystal phase, it is preferable to cool the composition so that the helical induction force of the chiral agent is increased by 10% or more.
When cooling the composition, it is preferable to cool the composition layer so that the temperature of the composition layer is lowered by 30 ° C. or more in that the diffuse reflectance of the reflective layer is more excellent. Especially, it is preferable to cool a composition layer so that it may become 40 degreeC or more at the point which the said effect is more excellent, and it is more preferable to cool a composition layer so that it may fall 50 degreeC or more. The upper limit value of the reduced temperature range of the cooling treatment is not particularly limited, but is usually about 70 ° C.
In other words, the above cooling treatment is intended to cool the composition layer so that it is T-30 ° C. or lower when the temperature of the composition layer in the cholesteric liquid crystal phase before cooling is T ° C. To do.
The cooling method is not particularly limited, and examples thereof include a method in which the substrate on which the composition layer is disposed is left in an atmosphere at a predetermined temperature.

Although the process for cooling or heating the composition layer has been described in detail above, the process for changing the bright part and the dark part derived from the cholesteric liquid crystal phase to be wavy is not limited to this mode.
For example, the process which applies a voltage with respect to a composition layer is also mentioned. The method for applying the voltage is not particularly limited, and examples thereof include a method in which a liquid crystal composition is filled in a horizontal alignment cell with ITO (Indium Tin Oxide), a composition layer is formed, and the voltage is applied.
In addition to the method of applying a voltage, a method of applying a magnetic field and a method of applying pressure are also included.

<Process 2>
Step 2 is a step of immobilizing the composition layer obtained in Step 1. By carrying out this step, the cholesteric liquid crystal phase in which the bright part and the dark part are wavy is fixed, and a desired reflective layer can be mentioned.
That is, the obtained reflective layer corresponds to a layer formed by fixing a cholesteric liquid crystal phase.
Here, the state in which the cholesteric liquid crystal phase is “fixed” is the most typical and preferred mode in which the orientation of the liquid crystal compound in the cholesteric liquid crystal phase is maintained. However, the layer is not fluid in a temperature range of usually 0 to 50 ° C., and -30 to 70 ° C. under more severe conditions, and is in an oriented form by an external field or external force. It means a state in which the fixed alignment form can be kept stable without causing a change. In the present invention, as described later, it is preferable to fix the alignment state of the cholesteric liquid crystal phase by a curing reaction that proceeds by ultraviolet irradiation.
In the layer formed by fixing the cholesteric liquid crystal phase, it is sufficient that the optical properties of the cholesteric liquid crystal phase are maintained in the layer, and the composition in the layer no longer needs to exhibit liquid crystallinity. Absent.

The method for the immobilization treatment is not particularly limited, and examples thereof include photocuring treatment and thermosetting treatment. Of these, light irradiation treatment is preferable, and ultraviolet irradiation treatment is more preferable. Such immobilization treatment is preferably a polymerization reaction by light irradiation (particularly ultraviolet irradiation), and more preferably a radical polymerization reaction by light irradiation (particularly ultraviolet irradiation).
For ultraviolet irradiation, a light source such as an ultraviolet lamp is used.
The amount of ultraviolet irradiation energy is not particularly limited, but generally it is preferably about 0.1 to 0.8 J / cm ² . The time for irradiation with ultraviolet rays is not particularly limited, but may be appropriately determined from the viewpoints of both sufficient strength and productivity of the resulting reflective layer.

During the immobilization treatment in step 2, the composition constituting the composition layer has a viscosity of 2000 mPa · s or more. As described above, if the viscosity of the composition constituting the composition layer is equal to or higher than the above value, the structure is fixed while the structure of the cholesteric liquid crystal phase in which the bright and dark portions obtained in step 1 are wavy is maintained. It becomes.
Among these, the viscosity is preferably 10,000 mPa · s or more, and more preferably 15000 mPa · s or more, in that the diffuse reflectance of the reflective layer is more excellent. The upper limit is not particularly limited, but is often 50000 mPa · s or less, more often 40000 mPa · s or less.

The viscosity of the composition constituting the composition layer can be adjusted by changing the type of components (liquid crystal compound, chiral agent, etc.) contained in the composition.
In particular, in order to achieve the above-mentioned viscosity, the content of the liquid crystal compound in the composition layer is preferably in the above-described preferable range. The liquid crystal compound is preferably a liquid crystal compound having a plurality of polymerizable groups.

As a method for measuring the viscosity of the composition constituting the composition layer, the viscosity of the composition constituting the composition layer is measured using a known viscosity measuring machine (for example, rheometer RS600 (manufactured by HAAKE)). The method of doing is mentioned.
In the above measurement, a part of the composition layer may be scraped off and used as a measurement sample, and the viscosity at a temperature during the immobilization treatment may be measured using the sample. Alternatively, a predetermined amount of each component constituting the composition layer may be mixed to prepare a measurement sample, and the viscosity at the temperature during the immobilization treatment may be measured using the sample.
In addition, the said viscosity is a viscosity in the case of an immobilization process, for example, when implementing an immobilization process (for example, light irradiation process) on 30 degreeC conditions, the viscosity at 30 degreeC is a fixed process. It corresponds to the viscosity at the time.

<Reflective layer>
With the above manufacturing method, a reflective layer having a wave-like structure in a bright part and a dark part in a cross-sectional SEM observation view as shown in FIG. 2 is formed.
The reflection layer is a layer having a cholesteric liquid crystal structure and a structure in which an angle formed by the spiral axis and the surface of the reflection layer is periodically changed. In other words, the reflective layer has a cholesteric liquid crystal structure, and the cholesteric liquid crystal structure gives a stripe pattern of a bright part and a dark part in a sectional view of the reflective layer observed with a scanning electron microscope, and a line formed by the bright part and the dark part. This is a reflective layer in which the angle between the normal line and the surface of the reflective layer changes periodically.

A plurality of reflective layers may be stacked.
For example, after forming the reflective layer X having a predetermined selective reflection wavelength on the substrate by the method described above, the reflective layer Y having a selective reflection wavelength different from the reflective layer X may be formed by the same procedure.

<Application>
The reflective layer (cholesteric liquid crystal layer) is a layer having a cholesteric liquid crystal phase (cholesteric liquid crystal structure) having a predetermined wave-like structure, and is preferably a layer formed by fixing this cholesteric liquid crystal phase.
The reflection layer is a layer that exhibits selective reflection characteristics with respect to light in a predetermined wavelength range. The reflection layer functions as a circularly polarized light selective reflection layer that selectively reflects either the right circularly polarized light or the left circularly polarized light and transmits the other circularly polarized light in the selective reflection wavelength region. A film containing one or more reflective layers can be used in various applications. In a film including two or more reflective layers, the sense of circularly polarized light reflected by each reflective layer may be the same or opposite depending on the application. Further, the center wavelength of selective reflection described later of each reflective layer may be the same or different depending on the application.

  In this specification, “sense” for circularly polarized light means right circularly polarized light or left circularly polarized light. The sense of circularly polarized light is right-handed circularly polarized light when the electric field vector tip turns clockwise as time increases when viewed as the light travels toward you, and left when it turns counterclockwise. Defined as being circularly polarized. In this specification, the term “sense” may be used for the twist direction of the spiral of the cholesteric liquid crystal. The selective reflection by the cholesteric liquid crystal reflects right circularly polarized light when the twist direction (sense) of the cholesteric liquid crystal spiral is right, transmits left circularly polarized light, and reflects left circularly polarized light when the sense is left, Transmits circularly polarized light.

For example, a film including a reflective layer exhibiting selective reflection characteristics in the visible light wavelength region (wavelength 400 to 750 nm) can be used as a screen for projecting image display and a half mirror. Further, by controlling the reflection band, it can also be used as a color filter or a filter for improving the color purity of display light of a display (see, for example, JP-A-2003-294948).
The reflective layer can be used for various applications such as a polarizing element, a reflective film, an antireflection film, a viewing angle compensation film, a holography, and an alignment film, which are constituent elements of an optical element.
Hereinafter, the use as a projection image display member, which is a particularly preferable use, will be described.

  With the above function of the reflective layer, it is possible to form a projected image by reflecting the circularly polarized light of one of the senses at a wavelength showing selective reflection in the projection light. The projected image may be displayed on the surface of the projected image display member and viewed as such, or may be a virtual image that appears above the projected image display member when viewed from the observer.

  The central wavelength λ of the selective reflection depends on the pitch P (= spiral period) of the helical structure in the cholesteric liquid crystal phase, and follows the relationship between the average refractive index n of the reflective layer and λ = n × P. Here, the center wavelength λ of selective reflection of the reflective layer means a wavelength at the position of the center of gravity of the reflection peak of the circularly polarized reflection spectrum measured from the normal direction of the reflective layer. As can be seen from the above equation, the center wavelength of selective reflection can be adjusted by adjusting the pitch of the helical structure. That is, by adjusting the n value and the P value, for example, to selectively reflect either the right circularly polarized light or the left circularly polarized light with respect to the blue light, the center wavelength λ is adjusted, and an apparent selection is made. The central wavelength of reflection can be in the wavelength range of 450 to 495 nm. The apparent center wavelength of selective reflection means the wavelength at the center of gravity of the reflection peak of the circularly polarized reflection spectrum of the reflection layer measured from the observation direction in practical use (when used as a projection image display member). To do. Since the pitch of the cholesteric liquid crystal phase depends on the kind of chiral agent used together with the liquid crystal compound or the concentration of the chiral agent, the desired pitch can be obtained by adjusting these. For the method of measuring the sense of the spiral and the pitch, the method described in “Introduction to Liquid Crystal Chemistry Experiments”, edited by the Japanese Liquid Crystal Society, Sigma Publishing 2007, page 46, and “Liquid Crystal Handbook”, Liquid Crystal Handbook Editorial Committee, page 196 Can be used.

  In addition, it is possible to display a full-color projected image by creating a reflective layer with an apparent selective reflection center wavelength in each of the red light wavelength range, the green light wavelength range, and the blue light wavelength range, and laminating them. It is possible to produce a projection image display member.

  By adjusting the central wavelength of selective reflection of each reflection layer according to the emission wavelength range of the light source used for projection and the usage mode of the projection image display member, it is possible to display a clear projection image with high light utilization efficiency. In particular, by adjusting the central wavelength of selective reflection of the reflective layer according to the emission wavelength range of the light source used for projection, a clear color projection image can be displayed with high light utilization efficiency.

  In addition, for example, when the projection image display member is configured to be transmissive to light in the visible light region, a half mirror that can be used as a combiner for a head-up display can be obtained. The projected image display half mirror can display the image projected from the projector so that it can be seen, and when the projected image display half mirror is observed from the same surface on which the image is displayed, the opposite surface is displayed. You can observe information or landscape on the side at the same time.

  Hereinafter, the features of the present invention will be described more specifically with reference to examples and comparative examples. The materials, amounts used, ratios, processing contents, processing procedures, and the like shown in the following examples can be appropriately changed without departing from the gist of the present invention. Accordingly, the scope of the present invention should not be construed as being limited by the specific examples shown below.

<Preparation of liquid crystal composition>
The components shown in Table 1 below were mixed to prepare liquid crystal compositions 1-6. In addition, all the quantity of each component is a mass part.

  Each component in Table 1 is shown below.

  Rod-shaped liquid crystal compound 101

  Rod-shaped liquid crystal compound 102

  Rod-shaped liquid crystal compound 201

  Rod-shaped liquid crystal compound 202

  Rod-shaped liquid crystal compound 203

  Rod-shaped liquid crystal compound 204

Polymer A

  Chiral agent A

  Chiral agent B

  Orientation control agent (1)

<Example 1>
On the rubbing-treated surface of a rubbed PET (poly-ethylene terephthalate) substrate (Toyobo), the liquid crystal composition 1 is dried at room temperature so that the thickness of the composition layer (coating layer) after drying is 4.5 μm. And applied using a wire bar. The composition layer was dried at room temperature for 50 seconds and then heated at 90 ° C. for 1 minute to align the liquid crystal compound. Thereafter, the composition layer was irradiated with UV (ultraviolet rays) for 8 seconds at 80 ° C. with a fusion D bulb (lamp 90 mW / cm ² ) at 30 ° C., and the reflective layer 1 (cholesteric liquid crystal phase was fixed on the PET substrate. Corresponding to the layer formed).
In the above procedure, after aligning the liquid crystal compound at 90 ° C., the liquid crystal composition is cooled to 30 ° C., and this treatment is a treatment for changing the helical induction force of the chiral agent contained in the composition layer. Applicable. HTP change rate between HTP at the orientation temperature (90 ° C.) of the chiral agent in the liquid crystal composition and HTP at the fixing temperature (30 ° C.) of the chiral agent in the liquid crystal composition cooled during UV irradiation. Was 15% or more. In addition, the said HTP change rate is calculated | required by the following formula | equation (3).
Formula (3): HTP change rate = {(HTP at the fixing temperature (30 ° C.) of the chiral agent in the liquid crystal composition) − (HTP at the orientation temperature (90 ° C.) of the chiral agent in the liquid crystal composition) / (HTP at the orientation temperature (90 ° C.) of the chiral agent in the liquid crystal composition)} × 100
In addition, the viscosity of the component which comprises the composition layer in 30 degreeC which is the temperature at the time of an immobilization process ("viscosity at the time of solidification" in Table 2) was measured according to the procedure mentioned above.
Moreover, the solvent was substantially removed from the composition layer by drying the composition layer at room temperature for 50 seconds.

<Examples 2 to 7, Comparative Example 1>
A reflective layer was formed according to the same procedure as in Example 1 except that the type of liquid crystal composition and the immobilization temperature were changed according to Table 2.
The following evaluation was performed using the obtained reflective layer.

<Orientation observation>
The obtained reflective layer is set on a polarizing microscope, and the reflective layer is applied under the conditions of 50 times the objective lens and 10 times the eyepiece under the epi-illumination conditions (conditions for observing the reflected light by irradiating light from above the reflective layer). Observed and evaluated according to the following criteria.
“S”: The undulation structure is clearly visible “A”: The undulation structure is visible “B”: The undulation structure is slightly visible “C”: The undulation structure is not visible When the undulation structure is visible A clear diffraction grating pattern can be confirmed.

<30 ° reflection amount>
A reflective layer was set to a light source side in a spectrophotometer V-670 (manufactured by JASCO Corporation) equipped with an absolute reflectance measurement system, and the reflectance was measured under 0 ° incidence and 30 ° detection conditions. That is, incident light from a light source is irradiated from the normal direction of the surface of the reflective layer, and each wavelength is reflected at a wavelength of 380 to 800 nm by a detector having a polar angle θ of 30 ° with respect to the normal direction of the surface of the reflective layer. The rate was measured. From the obtained data (horizontal axis: wavelength, vertical axis: reflectance), the peak area obtained by integrating the peaks of the respective wavelengths was calculated and obtained as a 30 ° reflection amount.
In addition, when calculating | requiring the said reflection amount, 30 degree reflection amount using only a board | substrate was measured separately and it used as a base line.

  In any of Examples 1 to 7, the HTP change rate (%) was 40% or less.

As shown in Table 2 above, according to the production method of the present invention, a reflective layer having excellent diffuse reflectance can be obtained.
In particular, it was confirmed that when the viscosity at the time of immobilization is 10,000 mPa · s or more (preferably 15000 mPa · s or more), the undulation structure is formed more clearly and the diffuse reflectance is further improved.

<Example 8>
In a horizontally aligned cell with ITO having a cell gap of 5 μm, the following liquid crystal composition 7 was sealed at 90 ° C. in a yellow light environment. Thereafter, the sealed liquid crystal composition 7 was subjected to an alignment treatment at 90 ° C. for 1 minute, and then the temperature was lowered to 30 ° C. In this cooling process, since the liquid crystal compound and the chiral agent of the liquid crystal composition 7 were in a predetermined combination, there was almost no change in HTP.
Next, when a voltage of 50 V was applied to the cell, it was confirmed from alignment observation that an undulation structure was formed in the liquid crystal composition 7. Thereafter, the temperature of the liquid crystal composition 7 is set to 30 ° C., and UV (ultraviolet light) is irradiated for 8 seconds at an output of 80% with a fusion D bulb (lamp 90 mW / cm ² ), the undulation structure is fixed, and the reflective layer is formed. Obtained. As a result of the observation of the orientation of the reflective layer, an undulation structure was confirmed.
Furthermore, the area of the reflection peak (30 ° reflection amount) under the 0 ° incidence 30 ° detection condition in the spectrophotometer V-670 was 10.2.
The viscosity of the liquid crystal composition 7 at 30 ° C. was 14100 mPa · s.

A liquid crystal composition 7 was prepared by mixing the following components.
Rod-like liquid crystal compound 201 90 parts by weight Rod-like liquid crystal compound 203 10 parts by weight Polymerization initiator Irg907 (manufactured by BASF) 3 parts by weight Polymerization sensitizer DETX-S (manufactured by Nippon Kayaku Co., Ltd.) 1 part by weight Chiral agent LC-756 (BASF) 4.5 parts by mass

DESCRIPTION OF SYMBOLS 10 Substrate 12a Cholesteric liquid crystal phase composition layer 12b Reflective layer 14 Bright portion 16 Dark portion

Claims (11)

A method for producing a reflective layer, in which a cholesteric liquid crystal phase is fixed and a bright portion and a dark portion derived from a cholesteric liquid crystal phase observed in a cross-section with a scanning electron microscope are wavy,
A composition layer containing a liquid crystal compound having a polymerizable group and a chiral agent is formed, and light and dark portions derived from a cholesteric liquid crystal phase observed with a scanning electron microscope in a cross section of the formed composition layer are wavy. Step 1 for performing the process to be changed,
Step 2 for performing immobilization treatment on the composition layer obtained in Step 1 above,
The method for producing a reflective layer, wherein the viscosity of the composition constituting the composition layer is 2000 mPa · s or more during the immobilization treatment in Step 2.   The method for producing a reflective layer according to claim 1, wherein the viscosity is 10,000 mPa · s or more.   The method for producing a reflective layer according to claim 1, wherein the viscosity is 15000 mPa · s or more.   The method for manufacturing a reflective layer according to claim 1, wherein the immobilization process is a light irradiation process.   The manufacturing method of the reflective layer of any one of Claims 1-4 whose said process in the said process 1 is a process which changes the helical induction force of the said chiral agent contained in the said composition layer.   The said process in the said process 1 is a process which cools or heats the said composition layer, and is a process which changes the helical induction force of the said chiral agent contained in the said composition layer. The manufacturing method of the reflection layer of claim | item.   The treatment in the step 1 heats the composition layer to align the liquid crystal compound into a cholesteric liquid crystal phase, and then the helical induction force of the chiral agent contained in the composition layer is 5%. The manufacturing method of the reflective layer of Claim 5 or 6 which is the process which cools the said composition layer so that it may raise above.   The method for producing a reflective layer according to claim 7, wherein when the composition layer is cooled, the composition layer is cooled such that the temperature of the composition layer is lowered by 30 ° C. or more.   The manufacturing method of the reflective layer of any one of Claims 1-4 whose said process in the said process 1 is a process which applies a voltage to the said composition layer.   The method for producing a reflective layer according to claim 1, wherein the liquid crystal compound has a plurality of polymerizable groups.   The manufacturing method of the reflective layer of any one of Claims 1-10 whose content of the said liquid-crystal compound in the said composition layer is 60 mass% or more.